Abstract
PurposeTo propose an alternative and practical model to conceptualize clinical patterns of concomitant intermittent strabismus, heterophoria, and convergence and accommodation anomalies.MethodsDespite identical ratios, there can be a disparity- or blur-biased “style” in three hypothetical scenarios: normal; high ratio of accommodative convergence to accommodation (AC/A) and low ratio of convergence accommodation to convergence (CA/C); low AC/A and high CA/C. We calculated disparity bias indices (DBI) to reflect these biases and provide early objective data from small illustrative clinical groups that fit these styles.ResultsNormal adults (n = 56) and children (n = 24) showed disparity bias (adult DBI 0.43 [95% CI, 0.50-0.36], child DBI 0.20 [95% CI, 0.31-0.07]; P = 0.001). Accommodative esotropia (n = 3) showed less disparity-bias (DBI 0.03). In the high AC/A–low CA/C scenario, early presbyopia (n = 22) showed mean DBI of 0.17 (95% CI, 0.28-0.06), compared to DBI of −0.31 in convergence excess esotropia (n=8). In the low AC/A–high CA/C scenario near exotropia (n = 17) showed mean DBI of 0.27. DBI ranged between 1.25 and −1.67.ConclusionsEstablishing disparity or blur bias adds to AC/A and CA/C ratios to explain clinical patterns. Excessive bias or inflexibility in near-cue use increases risk of clinical problems.
Highlights
ObjectivesThe purpose of this study was to present evidence in support of a conceptual model that suggests that individual biases in near-cue use predict clinical characteristics
All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law
In the high AC/A–low convergence accommodation to convergence (CA/C) scenario, early presbyopia (n 5 22) showed mean disparity bias index (DBI) of 0.17, compared to DBI of À0.31 in convergence excess esotropia (n58)
Summary
The purpose of this study was to present evidence in support of a conceptual model that suggests that individual biases in near-cue use predict clinical characteristics
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have